drivers/hwmon/ina2xx.c

   1 /*
   2  * Driver for Texas Instruments INA219, INA226 power monitor chips
   3  *
   4  * INA219:
   5  * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
   6  * Datasheet: http://www.ti.com/product/ina219
   7  *
   8  * INA220:
   9  * Bi-Directional Current/Power Monitor with I2C Interface
  10  * Datasheet: http://www.ti.com/product/ina220
  11  *
  12  * INA226:
  13  * Bi-Directional Current/Power Monitor with I2C Interface
  14  * Datasheet: http://www.ti.com/product/ina226
  15  *
  16  * INA230:
  17  * Bi-directional Current/Power Monitor with I2C Interface
  18  * Datasheet: http://www.ti.com/product/ina230
  19  *
  20  * Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
  21  * Thanks to Jan Volkering
  22  *
  23  * This program is free software; you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License as published by
  25  * the Free Software Foundation; version 2 of the License.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/err.h>
  32 #include <linux/slab.h>
  33 #include <linux/i2c.h>
  34 #include <linux/hwmon.h>
  35 #include <linux/hwmon-sysfs.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/of.h>
  38 #include <linux/delay.h>
  39 #include <linux/util_macros.h>
  40 #include <linux/regmap.h>
  41
  42 #include <linux/platform_data/ina2xx.h>
  43
  44 /* common register definitions */
  45 #define INA2XX_CONFIG                   0x00
  46 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  47 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  48 #define INA2XX_POWER                    0x03 /* readonly */
  49 #define INA2XX_CURRENT                  0x04 /* readonly */
  50 #define INA2XX_CALIBRATION              0x05
  51
  52 /* INA226 register definitions */
  53 #define INA226_MASK_ENABLE              0x06
  54 #define INA226_ALERT_LIMIT              0x07
  55 #define INA226_DIE_ID                   0xFF
  56
  57 /* register count */
  58 #define INA219_REGISTERS                6
  59 #define INA226_REGISTERS                8
  60
  61 #define INA2XX_MAX_REGISTERS            8
  62
  63 /* settings - depend on use case */
  64 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  65 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  66
  67 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  68 #define INA2XX_CONVERSION_RATE          15
  69 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  70
  71 #define INA2XX_RSHUNT_DEFAULT           10000
  72
  73 /* bit mask for reading the averaging setting in the configuration register */
  74 #define INA226_AVG_RD_MASK              0x0E00
  75
  76 #define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  77 #define INA226_SHIFT_AVG(val)           ((val) << 9)
  78
  79 /* common attrs, ina226 attrs and NULL */
  80 #define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  81
  82 /*
  83  * Both bus voltage and shunt voltage conversion times for ina226 are set
  84  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  85  */
  86 #define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  87
  88 static struct regmap_config ina2xx_regmap_config = {
  89         .reg_bits = 8,
  90         .val_bits = 16,
  91 };
  92
  93 enum ina2xx_ids { ina219, ina226 };
  94
  95 struct ina2xx_config {
  96         u16 config_default;
  97         int calibration_factor;
  98         int registers;
  99         int shunt_div;
 100         int bus_voltage_shift;
 101         int bus_voltage_lsb;    /* uV */
 102         int power_lsb;          /* uW */
 103 };
 104
 105 struct ina2xx_data {
 106         const struct ina2xx_config *config;
 107
 108         long rshunt;
 109         struct mutex config_lock;
 110         struct regmap *regmap;
 111
 112         const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 113 };
 114
 115 static const struct ina2xx_config ina2xx_config[] = {
 116         [ina219] = {
 117                 .config_default = INA219_CONFIG_DEFAULT,
 118                 .calibration_factor = 40960000,
 119                 .registers = INA219_REGISTERS,
 120                 .shunt_div = 100,
 121                 .bus_voltage_shift = 3,
 122                 .bus_voltage_lsb = 4000,
 123                 .power_lsb = 20000,
 124         },
 125         [ina226] = {
 126                 .config_default = INA226_CONFIG_DEFAULT,
 127                 .calibration_factor = 5120000,
 128                 .registers = INA226_REGISTERS,
 129                 .shunt_div = 400,
 130                 .bus_voltage_shift = 0,
 131                 .bus_voltage_lsb = 1250,
 132                 .power_lsb = 25000,
 133         },
 134 };
 135
 136 /*
 137  * Available averaging rates for ina226. The indices correspond with
 138  * the bit values expected by the chip (according to the ina226 datasheet,
 139  * table 3 AVG bit settings, found at
 140  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 141  */
 142 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 143
 144 static int ina226_reg_to_interval(u16 config)
 145 {
 146         int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 147
 148         /*
 149          * Multiply the total conversion time by the number of averages.
 150          * Return the result in milliseconds.
 151          */
 152         return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 153 }
 154
 155 /*
 156  * Return the new, shifted AVG field value of CONFIG register,
 157  * to use with regmap_update_bits
 158  */
 159 static u16 ina226_interval_to_reg(int interval)
 160 {
 161         int avg, avg_bits;
 162
 163         avg = DIV_ROUND_CLOSEST(interval * 1000,
 164                                 INA226_TOTAL_CONV_TIME_DEFAULT);
 165         avg_bits = find_closest(avg, ina226_avg_tab,
 166                                 ARRAY_SIZE(ina226_avg_tab));
 167
 168         return INA226_SHIFT_AVG(avg_bits);
 169 }
 170
 171 static int ina2xx_calibrate(struct ina2xx_data *data)
 172 {
 173         u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 174                                     data->rshunt);
 175
 176         return regmap_write(data->regmap, INA2XX_CALIBRATION, val);
 177 }
 178
 179 /*
 180  * Initialize the configuration and calibration registers.
 181  */
 182 static int ina2xx_init(struct ina2xx_data *data)
 183 {
 184         int ret = regmap_write(data->regmap, INA2XX_CONFIG,
 185                                data->config->config_default);
 186         if (ret < 0)
 187                 return ret;
 188
 189         /*
 190          * Set current LSB to 1mA, shunt is in uOhms
 191          * (equation 13 in datasheet).
 192          */
 193         return ina2xx_calibrate(data);
 194 }
 195
 196 static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
 197 {
 198         struct ina2xx_data *data = dev_get_drvdata(dev);
 199         int ret, retry;
 200
 201         dev_dbg(dev, "Starting register %d read\n", reg);
 202
 203         for (retry = 5; retry; retry--) {
 204
 205                 ret = regmap_read(data->regmap, reg, regval);
 206                 if (ret < 0)
 207                         return ret;
 208
 209                 dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
 210
 211                 /*
 212                  * If the current value in the calibration register is 0, the
 213                  * power and current registers will also remain at 0. In case
 214                  * the chip has been reset let's check the calibration
 215                  * register and reinitialize if needed.
 216                  * We do that extra read of the calibration register if there
 217                  * is some hint of a chip reset.
 218                  */
 219                 if (*regval == 0) {
 220                         unsigned int cal;
 221
 222                         ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
 223                                           &cal);
 224                         if (ret < 0)
 225                                 return ret;
 226
 227                         if (cal == 0) {
 228                                 dev_warn(dev, "chip not calibrated, reinitializing\n");
 229
 230                                 ret = ina2xx_init(data);
 231                                 if (ret < 0)
 232                                         return ret;
 233                                 /*
 234                                  * Let's make sure the power and current
 235                                  * registers have been updated before trying
 236                                  * again.
 237                                  */
 238                                 msleep(INA2XX_MAX_DELAY);
 239                                 continue;
 240                         }
 241                 }
 242                 return 0;
 243         }
 244
 245         /*
 246          * If we're here then although all write operations succeeded, the
 247          * chip still returns 0 in the calibration register. Nothing more we
 248          * can do here.
 249          */
 250         dev_err(dev, "unable to reinitialize the chip\n");
 251         return -ENODEV;
 252 }
 253
 254 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
 255                             unsigned int regval)
 256 {
 257         int val;
 258
 259         switch (reg) {
 260         case INA2XX_SHUNT_VOLTAGE:
 261                 /* signed register */
 262                 val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
 263                 break;
 264         case INA2XX_BUS_VOLTAGE:
 265                 val = (regval >> data->config->bus_voltage_shift)
 266                   * data->config->bus_voltage_lsb;
 267                 val = DIV_ROUND_CLOSEST(val, 1000);
 268                 break;
 269         case INA2XX_POWER:
 270                 val = regval * data->config->power_lsb;
 271                 break;
 272         case INA2XX_CURRENT:
 273                 /* signed register, LSB=1mA (selected), in mA */
 274                 val = (s16)regval;
 275                 break;
 276         case INA2XX_CALIBRATION:
 277                 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 278                                         regval);
 279                 break;
 280         default:
 281                 /* programmer goofed */
 282                 WARN_ON_ONCE(1);
 283                 val = 0;
 284                 break;
 285         }
 286
 287         return val;
 288 }
 289
 290 static ssize_t ina2xx_show_value(struct device *dev,
 291                                  struct device_attribute *da, char *buf)
 292 {
 293         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 294         struct ina2xx_data *data = dev_get_drvdata(dev);
 295         unsigned int regval;
 296
 297         int err = ina2xx_read_reg(dev, attr->index, &regval);
 298
 299         if (err < 0)
 300                 return err;
 301
 302         return snprintf(buf, PAGE_SIZE, "%d\n",
 303                         ina2xx_get_value(data, attr->index, regval));
 304 }
 305
 306 static ssize_t ina2xx_set_shunt(struct device *dev,
 307                                 struct device_attribute *da,
 308                                 const char *buf, size_t count)
 309 {
 310         unsigned long val;
 311         int status;
 312         struct ina2xx_data *data = dev_get_drvdata(dev);
 313
 314         status = kstrtoul(buf, 10, &val);
 315         if (status < 0)
 316                 return status;
 317
 318         if (val == 0 ||
 319             /* Values greater than the calibration factor make no sense. */
 320             val > data->config->calibration_factor)
 321                 return -EINVAL;
 322
 323         mutex_lock(&data->config_lock);
 324         data->rshunt = val;
 325         status = ina2xx_calibrate(data);
 326         mutex_unlock(&data->config_lock);
 327         if (status < 0)
 328                 return status;
 329
 330         return count;
 331 }
 332
 333 static ssize_t ina226_set_interval(struct device *dev,
 334                                    struct device_attribute *da,
 335                                    const char *buf, size_t count)
 336 {
 337         struct ina2xx_data *data = dev_get_drvdata(dev);
 338         unsigned long val;
 339         int status;
 340
 341         status = kstrtoul(buf, 10, &val);
 342         if (status < 0)
 343                 return status;
 344
 345         if (val > INT_MAX || val == 0)
 346                 return -EINVAL;
 347
 348         status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
 349                                     INA226_AVG_RD_MASK,
 350                                     ina226_interval_to_reg(val));
 351         if (status < 0)
 352                 return status;
 353
 354         return count;
 355 }
 356
 357 static ssize_t ina226_show_interval(struct device *dev,
 358                                     struct device_attribute *da, char *buf)
 359 {
 360         struct ina2xx_data *data = dev_get_drvdata(dev);
 361         int status;
 362         unsigned int regval;
 363
 364         status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
 365         if (status)
 366                 return status;
 367
 368         return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
 369 }
 370
 371 /* shunt voltage */
 372 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 373                           INA2XX_SHUNT_VOLTAGE);
 374
 375 /* bus voltage */
 376 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 377                           INA2XX_BUS_VOLTAGE);
 378
 379 /* calculated current */
 380 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 381                           INA2XX_CURRENT);
 382
 383 /* calculated power */
 384 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 385                           INA2XX_POWER);
 386
 387 /* shunt resistance */
 388 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 389                           ina2xx_show_value, ina2xx_set_shunt,
 390                           INA2XX_CALIBRATION);
 391
 392 /* update interval (ina226 only) */
 393 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 394                           ina226_show_interval, ina226_set_interval, 0);
 395
 396 /* pointers to created device attributes */
 397 static struct attribute *ina2xx_attrs[] = {
 398         &sensor_dev_attr_in0_input.dev_attr.attr,
 399         &sensor_dev_attr_in1_input.dev_attr.attr,
 400         &sensor_dev_attr_curr1_input.dev_attr.attr,
 401         &sensor_dev_attr_power1_input.dev_attr.attr,
 402         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 403         NULL,
 404 };
 405
 406 static const struct attribute_group ina2xx_group = {
 407         .attrs = ina2xx_attrs,
 408 };
 409
 410 static struct attribute *ina226_attrs[] = {
 411         &sensor_dev_attr_update_interval.dev_attr.attr,
 412         NULL,
 413 };
 414
 415 static const struct attribute_group ina226_group = {
 416         .attrs = ina226_attrs,
 417 };
 418
 419 static int ina2xx_probe(struct i2c_client *client,
 420                         const struct i2c_device_id *id)
 421 {
 422         struct device *dev = &client->dev;
 423         struct ina2xx_data *data;
 424         struct device *hwmon_dev;
 425         u32 val;
 426         int ret, group = 0;
 427
 428         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 429         if (!data)
 430                 return -ENOMEM;
 431
 432         /* set the device type */
 433         data->config = &ina2xx_config[id->driver_data];
 434
 435         if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 436                 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
 437
 438                 if (pdata)
 439                         val = pdata->shunt_uohms;
 440                 else
 441                         val = INA2XX_RSHUNT_DEFAULT;
 442         }
 443
 444         if (val <= 0 || val > data->config->calibration_factor)
 445                 return -ENODEV;
 446
 447         data->rshunt = val;
 448
 449         ina2xx_regmap_config.max_register = data->config->registers;
 450
 451         data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 452         if (IS_ERR(data->regmap)) {
 453                 dev_err(dev, "failed to allocate register map\n");
 454                 return PTR_ERR(data->regmap);
 455         }
 456
 457         ret = ina2xx_init(data);
 458         if (ret < 0) {
 459                 dev_err(dev, "error configuring the device: %d\n", ret);
 460                 return -ENODEV;
 461         }
 462
 463         mutex_init(&data->config_lock);
 464
 465         data->groups[group++] = &ina2xx_group;
 466         if (id->driver_data == ina226)
 467                 data->groups[group++] = &ina226_group;
 468
 469         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 470                                                            data, data->groups);
 471         if (IS_ERR(hwmon_dev))
 472                 return PTR_ERR(hwmon_dev);
 473
 474         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 475                  id->name, data->rshunt);
 476
 477         return 0;
 478 }
 479
 480 static const struct i2c_device_id ina2xx_id[] = {
 481         { "ina219", ina219 },
 482         { "ina220", ina219 },
 483         { "ina226", ina226 },
 484         { "ina230", ina226 },
 485         { "ina231", ina226 },
 486         { }
 487 };
 488 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 489
 490 static struct i2c_driver ina2xx_driver = {
 491         .driver = {
 492                 .name   = "ina2xx",
 493         },
 494         .probe          = ina2xx_probe,
 495         .id_table       = ina2xx_id,
 496 };
 497
 498 module_i2c_driver(ina2xx_driver);
 499
 500 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 501 MODULE_DESCRIPTION("ina2xx driver");
 502 MODULE_LICENSE("GPL");